Electric incandescent lamp



Aug. 30,1927- H, woRKMAN ELECTRIC INCANDESCENT LAMP I Filed Feb. '7,1923 Patented Aug. 30, 1927.

HAROLD WORKMAN, F GLASGOW, SCOTLAND.

ELECTRIC INCANDESCENT LAMP.

Application led February?, 1923, Serial No. 617,631, and in GreatBritain July 5, 1922.

This invention relates to electric incandescent lamps and to lampholders therefor. The principal object of the invention is to providefor the correct locating of the fila- 5 ment of an electric incandescentlamp in relation to its lamp holder or to an`optical reflector or lenssystem by which the light emitted from thelamp is directed andcontrolled. This invention is particularly apl0 plicable tov lamps usedfor light projection purposes and more particularly to motor car headlamps.

Electric incandescent filament lamps for signalling purposes are atpresent made sothat when the lamp is inserted in position in its holderthe filament occupies the desired position in relation to the holder andreflector but in this case a special cap fitted with a long stem and aspecial lamp holder 2 are employed.

- In the case of motor car head lamps it is usually required to locate aclosely wound type of filament correctly in relation to a reflectorofrparabolic or other form. It may be required for example to bring theaxis of a pillar filament into line with lthe axis of the reflector,while bringing the ends of the filament within a prescribed range eitherin front or behind a focal point, or between 3o two foci in the case ofa lamp having a reunderstood and readily carried into effect',

flector made-up in parts whose foci are at different points on the axis.

The present invention enables lamp bulbs fitted with caps of the usualtype and with single, or double pole contacts, to be used in conjunctionwith lampholders provided ,with spring pressed terminals and at the sametime enables the lamps to be adjustedy so that when `fitted in positionin the lamp holders their filaments will be in the required positionwithout any subsequent adjustment.

'To this end the invention mainly consists in an electric incandescentfilament I 45 lamp bulb having a cap and single or double some examplesof incandescent electric lamps furnished with fitting pieces" inaccordance with the present invention are illustrated in theaccompanying drawings, in which :-e

Figure 1 is an elevation of the lamp showing the fitting piece insection;

Figure 2 is a plan of Figure 1, with. the lamp bulb removed;

Figures 3 and 4 are similar views of a second form oflamp; while yFigure 5 is a view similar to Figure 1, of yet another form.

Referring first to Figures 1 and 2, a lamp a is shown having a cap bwith the usual double pole contacts o, d. The fitting piece is in theform of a tubular ferrule e and is secured to the lamp cap b by anadhesive binding materia/l, in the actualv case illustrated, by solderwhich is seen at f. The ferrule e has its lower end of reduceddiameterffor a short length so as to fit rather loosely upon the cap b,so that prior to securing the fer-.rule e to the cap b, the lamp as awhole and consequently the filament can be adjusted relatively to theferrule in an axial direction and the lamp can be slightly swungrelatively to the ferrule to adjust the position of the filament guntil` it lies exactly in the axis of the ferrule e. The upper end 'ofthe ferrule e has lugs h, la, Z, of which the lug h is wider than theother two and these lugs serve for securing the lamp in the bayonet lampholder. The form of lamp illustrated in Figures 1 and 2 is particularlyadapted for use in a lamp holder, such as is illustrated in'Figures 1 to'7 of the drawings accompanying my patent application Serial No.617,632, filed February 7, 1923. Such a lamp holder enables theadvantages of the present invention to be fullyemployed because suchalamp holder is arranged to be firmly fixed in its correct positionrelatively to a parabolic reflector or the like.

The bulb a and the fitting piece e are temporarily Aheld. in a suitablevfixture in which the bulb` can be adjusted along the axis of thefitting piece e and the filament can be swungvrelatively to that axis asalready referred to. Then relative adjustment is carried out until thefitting occupies the desired position relatively to the 'lamp filament.The fitting piece e is then secured by n.

cement, solder or the like to the cap b. The lug h is made wider than orof a different shape from the other two lugs to ensure that the lampshall be placed in the correct angular position in the lamp holder sothat the terminals c, d shall register correctly wlth 'the contact studsof the lamp holder, as in.

this case, .double pole contacts are illustrated fitted in the lamp cap.

If desired the lower reduced end of the ferrule e may be made with holesor notches into or through which the solder f can ow |`illustrated isonly 4:furnished with one con tact p arranged centrally. the other endof the filament being, of course. asis usual connected to the outercasing of the lamp cap b. A cap having double pole contacts could ofcourse also be used with this form of fitting piece if desired. Further,in these figures, the reduced part of the ferrule e is at the end nearerthe lamp bulb, so that the lugscor-V responding to la, lc, Z, are at theend of the i cap remote from the bulb a. v`Also instead of three lu s h,lo, Z, only two lugs m, n, are

rovide giving only a two point contact ut such contact extends over asector shaped area at each side including an angle of almost .a rightangle. Consequently the .form of lamp illustrated in Figures 3 and 4 canbe more conveniently used, or example,

' with a lamp holder of the construction illustrated in Figures 14 and15 of the drawings accom anying the specification of my patent apication Serial No. 617,632, filed February gth, l1923.

In Figure 5, another modification of the form of tting piece illustratedin Figure 1 is shown. The fitting piece is again in the form of atubular ferrule e and has three horizontallugs near its upper endxofmuch the same shape. as the lugs h, lc, Z, in Figures 1 and 2. However,these lugs are formed by slittingv the ferrule e from its upper edge andturning down the lugs outwardly. The parts of the ferrule between thelugs are allowed to remain 'standing projecting up Wardly as seen at g,1'. This construction has the advantage that these upstanding portions,part cylindrical in shape, can engage -with the internal interruptedflange of a' lamp holder, as illustrated in Figures 8 to 11 of thedrawings accompanying the speciiication of my patent a plication SerialNo. 617,632, filed February gth, 1923.

Although the invention has been described as applied to lamp bulbs foruse in motor car head lam s, yet it will be obvious thvat it is also appicable to lamp bulbs and lamp holders for an .purpose re uiring accuratelocating of a lamentk in re ation to an optical projection system. `Apractical advantage of the invention is that the pole pieces as inordinary lamp bulbs may be used for contact making purposes withordinary spring terminals in the lamp holder,

ament mounted therein, a lampcap of usual constructions with 4a metalliccasing secured to said bulb, a lamp contact carried in said lamp cap anda sleeve shaped tting piece formed to fit Within a lamp holder andhaving a part making annular contact with the outside of said lamp cap,said part having such narrow axial width that the lamp cap securing saidtting piece to said lamp cap yis capable of rocking thereinand means forin a pre-determined position both axially and laterally with respect tosaid filament.

2. An electric incandescent lamp comprising in combination a bulb, afilament mounted therein, a lamp cap of usual construction secured tosaid bulb, a lamp contact carried in said lamp cap and a tubular fittingreduced at one end to fit loosely said lamp capand to form a restingplace for solder by which said fitting piece is secured to said lamp capin a pre-determined position both axially and laterally with referenceto said filament.

3. An incandescent electric lamp comprising in combination a bulb, alament mounted therein, a lamp cap of usual construction secured to saidbulb, a lampl contact carried in said lamp cap and a tubular ttin lpiece encircling said lamp cap formed wit outwardly turned lugs adjacent'the end of the fitting piece nearest to the lamp bulb and reduced atthe opposite' end to lit loosely said lamp cap and to lform a restingplace for solder by means of which said fitting l piece, is secured tosaid lampcap in a predetermined position both axially and laterally withreference to said filament.

4. An electric incandescent lamp comprised therein, a lamp cap of usualconstructi n secured in said bulb, a pair of lamp contacts carried insaid lamp cap and a metallic tubular fitting piece formed at one endwith three outwardly turned flat spaced lugs, one

ving in combination a bulb, a filament mou tbeing of differentdimensions from the HAROLD woRKiniN.

and laterally with reierf4

